278 Genetic Studies in Poultry 



more than state that we have encountered no phenomena of the kind in 

 the course of our work. 



Inheritance of Egg -Colour. 



The experiments, of which an account is now given, were designed 

 for the investigation of egg-colour and of broodiness on the same 

 material.- For convenience the crosses made will be considered first in 

 connection with egg-colour. In 1910 and 1911 F^ birds were produced 

 from the mating Brown Leghorn % x Black Langshan (/*, and in 1912 

 from the reciprocal. The Brown Leghorn hens belonged to a strain 

 which had been under observation for some years previously. The eggs 

 were white, and broodiness was never observed. The Langshans were 

 purchased in 1910, and during this season and the following one they 

 were used for breeding pure Langshan as well as for crossing. Those 

 bred all laid brown eggs of a depth similar to that of the egg figured on 

 PI. IX, fig. 5, though perhaps not quite so pink in tone. The variation 

 in the depth of the colour in the various birds was slight. Subsequently 

 a further set of experiments was made in which the non-broody white 

 e^g breed used was the Gold Pencilled Hamburgh, the brown e^g 

 broody race being, as before, the Langshan. 



At this point a brief digression is necessary in order to explain the procedure 

 adopted in recording the colour of the egg. After consideration of several methods 

 we decided to make use of the standard colour charts published by the Societe 

 fran9aise des Chrysanthemistes. It was not always possible to match the tint of 

 a given egg exactly, for some had slightly more pink, and others again slightly more 

 yellow than the nearest colour on the chart. Nevertheless we felt that the record 

 was sufficiently accurate for our purpose, since it was the depth of colour rather 

 than the exact tint that we wished to register. €ix sheets of the chart, each with 

 four diflferent shades, were made use of, viz. : 



Jaune mais, 36^. 

 Saumon jaun§,tre, 65. 

 Chair tendre, 68. 

 Saumon rouge4tre, 73. 

 Chair rose, 136. 

 Rose de Nymphe, 137. 

 The sheets were carefully collated by eye and the following 12 grades were 

 established for use in the experiments : 



Grade 1. White. 



„ 2. Very slightly tinted. 

 „ 3. R. de N. 1. 

 „ 4. R. de N. 2. 



1 The number after each colour denotes the number of the sheet in the publication 

 referred to. - 



